|
|
Oct 29, 2019 18:31:19 GMT
|
so ive bought a turbo, its a garret 1544, it does weight a little bit, so ill have to brace the exhaust manifold a bit as i do plan to use the lcb that i have.
Now, researching the metro turbo, it had no intercooler, and it ran on a dizzy. Dizzy new on ebay electronic ignition with coil and leads are £100, the metro turbo plenum can be £120 on ebay, can it just be that simple after converting a normal carb to a turbo one?
People seem to use megajolt, home made plenums, intercoolers, but i am not after big power i just want that 60-80 bhp and it to drive well enough to have some fun...
|
|
|
|
|
Russ
Part of things
Posts: 372
|
|
Oct 29, 2019 21:41:03 GMT
|
Definitely go down the megajolt route. The standard metro turbo dizzy was a compromise between performance and preventing detonation when new, a 30+ year old one of ebay will be a waste of money. The new ebay dizzy's will need re-curving, the advance curves are all over the place on these out the box and 9 times out of 10 aren't even suitable for a standard engine, let alone a turbo'd one.
A rough spec i'd suggest would be something like this:
HIF44 turbo carb or convert a standard one with a metro turbo plenum chamber
Small intercooler (standard VW tdi type one or similar)
Standard 12G295 cylinder head (ideally un-skimmed) or a small valve 12G904 (block pockets required)
MG metro or Kent 266 camshaft
All bolted to a decent bottom end & gearbox.
You'll easily get 80bhp with that spec running around 8 psi boost.
|
|
|
|
|
|
Oct 29, 2019 22:01:21 GMT
|
80 bhp too much power! i don't need that, it just wants to keep up with modern traffic, i think now maybe 50-60 is enough. just been watching some mg metro turbo vids on youtube, and i noticed that when the air filter is on, you cant really tell! ideal! So intercooler is out really if i can help it. In my mind now i have 998 a+ rebuilt standard head ported and chambers opened up for decompression or i have a 12g940 that is rebuilt i could open up the chambers mg metro cam if i can get one or just the standard cam ill talk to the guy who built my volvo rally engine and see if he can mod a standard dizzy for less advance like the original turbo metro ones it maybe only do 500 miles a year, and keeping the 998 reliable is the most important thing to me ))
|
|
|
|
Russ
Part of things
Posts: 372
|
|
Oct 29, 2019 23:24:39 GMT
|
You can never have too much power, just ease off the throttle pedal.
If all you want is 50-60 bhp, then that is quite easily achieved without using a turbo on a 998cc. A bog standard 1275cc will put out 65-ish bhp without even trying and it'll cost the same as rebuilding a 998cc while producing more torque too.
If you really want to use a turbo, keep the engine a 998 and only want 50-60bhp, then just have the engine rebuilt as standard and have a megajolt controlling the ignition and run a low amount of boost.
If you want to keep the 998 but don't mind losing the turbo, then i can suggest an ideal road spec engine for you...
|
|
|
|
slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
|
a+ 998 turboslater
@slater
Club Retro Rides Member 78
|
Oct 31, 2019 16:44:13 GMT
|
Forget the dizzy. It's pointless in the 21st century.
|
|
|
|
|
|
Oct 31, 2019 20:01:38 GMT
|
ive never had a turbo car before so that is why i was thinking of this. I do have a 1293 with big head cam etc, but i don't for some reason fancy running it.
just fancied the turbo idea as a bit of a laugh, and to learn about them. The amount of power it wants to make is just so it keeps really reliable.
My mate in Bulgaira has put turbo to his lada 2105, but uses megasquirt, he was saying some lads there use renult renix ignition systems, I'm not saying i want to do that but ive never heard of it before. He made the point also that if i was to go for megajolt, may as well go for microsquirt as megajolt is very old, and mircosquirt can do a lot more.
I read, but cant find again something about dizzys on turbo cars having some other form of vac advance pipe or something, but i cant find it again. think it was on saabs.
i keep looking at the dizzy stuff as not only is it a lot less money, time to set up, etc, but it must have worked or there would not have been a metro turbo. Part of it also, its an austin rover part for an austin rover car, its simple.
i don't understand what happens to the advance curve under the boost that makes the difference.
|
|
|
|
Phil H
Posted a lot
Posts: 1,448
Club RR Member Number: 133
|
a+ 998 turboPhil H
@philhoward
Club Retro Rides Member 133
|
|
Generally you need to retard the timing under boost; I think it’s a Bosch advance unit off a SAAB that is a vacuum advance/boost retard unit.
I thought the A-series turbo had an ignition ECU with an actual ignition map - or am I getting confused with the O series turbo stuff?
|
|
|
|
ChasR
RR Helper
motivation
Posts: 10,188
Club RR Member Number: 170
|
a+ 998 turboChasR
@chasr
Club Retro Rides Member 170
|
|
If it were me, I'd do the above as suggested, but do two things a little differently. -Dizzy. If Nodiz can retard the ignition on boost, I'd go with that . You can also get better starting/idling that way potentially -Intercooler. With the boost levels you have, I doubt an intercooler is required. The carb itself will cool the mixture down significantly and act as an intercooler in that case, especially with the boost levels you have in mind. This effect won't really happen with fuel injection -Injection; due to the above I wouldn't use it, in addition to the Siamese head arrangement potentially causing issues -AFR Gauge ; just to get things dialled in right. TBH I think you'd struggle to not go to 80 or 90BHP. The Metro Turbos were deliberately downpowered from the factory as the gearboxes couldn't take the power in a Metro.
|
|
|
|
ChasR
RR Helper
motivation
Posts: 10,188
Club RR Member Number: 170
|
a+ 998 turboChasR
@chasr
Club Retro Rides Member 170
|
|
i don't understand what happens to the advance curve under the boost that makes the difference. It's a hard one to explain, and that probably shows that I don't understand it as much as I sometimes think. But here it goes . Hopefully it won’t come across like I am teaching you have to suck eggs. Let me know if that is the case. There is an idea time in a car for lighting up the air and fuel mixture. Light it up too soon, and the bang won't be as good as it could have been. Light it up too early and it either will not light up as good as it could have done or worse create a bigger bang than your engine can handle. The latter part (the bigger bang part), is what causes the engine rattling (pistons against the block and possibly even bearings against con-rods. I’m talking about premature detonation (stop sniggering in the back there). This of course, goes under various names like pre-detontation, pre-det, knocking, pinging, pinking and whatever new terms come out against it. For a given size of a bang under the same pressure conditions (i.e the combustion of air and fuel), the time it takes to ignite will be the same. This is why on normal engines, the ignition advance goes up as the car revs ; the bang takes the same amount of time to happen. Of course, the pistons are travelling faster as you rev the car more. This is where to get the optimum combusition, it is necessary to light that mixture earlier. This condition where the spark plug is fired earlier is called ignition advance (it’s being fired in advance of when it would be at idle, where the piston speed is lower at idle). With boost, your bang is bigger as you have more air and fuel in the mix. Remember where I said for the pressure remaining the same. Well, that kind of changes with your compression ratio, so as to make the combustion a little more stable. But with the bigger bang for a similar pressure and size, that bang tends to happen earlier/quicker and can become more unstable, thus pinking is more likely. This is why it’s necessary to not have as much advance under boost as you would for an N/A engine. The window in which you can play it safe is also less for a boosted engine, due to it being less stable. That said, many cars run turbos for hundreds of thousands of miles without a hitch, so despite the above making it sound like a black art, it’s certainly easily doable, especially since others have done it before in this case. There is probably a triangle out there somewhere which shows what can influence power/pre-det for the above.
|
|
|
|
slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
|
a+ 998 turboslater
@slater
Club Retro Rides Member 78
|
|
The megajolt route wont be segnificantly more expensive than the dizzy route usually. Assuming you actually want it done properly that is.
|
|
|
|
|
craig1010cc
Club Retro Rides Member
Posts: 2,992
Club RR Member Number: 35
|
a+ 998 turbocraig1010cc
@craig1010cc
Club Retro Rides Member 35
|
|
If your looking to do it on the cheap, a stock 1098 head will drop the compression on a 998, but does have slightly bigger inlet valves and bigger ports.
For the power levels your looking for, I’d not worry about an inter cooler (makes the piping much easier) and I’d leave the stock cam in it too. A Hiff44 might be a bit overkill too, but you should be able to do the same mods to a hiff38 although your going to need to adapt the plenum to suit
|
|
|
|
|
|
|
wow thanks for the replies, this is why i was a bit reluctant to start on the turbo mini forum as i know there is so much knollage here. thanks chas not over simply explaining it but exactly what i wanted to know so i can see why a dizzy maybe the compromise then. megajolt ive seen for sale for £250 plus, so it would be worth paying more for microsquirt for me as i could use it in so many other ways. However, has anyone used this speeduino setup? click herei am a big fan or arduinos, and also i have a smd rework station here, and its all threw hole by the looks. That looks a good price and can do everything. The car if it has a ecu on it will goto efi in runcorn to get set up, so as long as chris can play with it ok, its a goer unless someone has had bad experiences? How far from the engine and bulkhead can the turbo be? i mean on the back of a 998 there is those little inspection holes with cork gaskets, and also the bolkhead that i don't want to get the paint damaged on. I am kinda thinking ok, its going to get this turbo now, maybe give it some more room and hack a bit away that can be replaced later if needed. thanks..
edit, oh also 1098 head would be good, but ive a rebuilt 12g940 i can use, and i could pocket the block i think with the maggy drill at work.... maybe !!
|
|
Last Edit: Nov 1, 2019 20:35:52 GMT by bmw2101
|
|
Phil H
Posted a lot
Posts: 1,448
Club RR Member Number: 133
|
a+ 998 turboPhil H
@philhoward
Club Retro Rides Member 133
|
|
I read some of the posts on a Facebook Speeduino group and it seems a bit “buggy” in the firmware department still; a little disconcerting given it’s basically a Megasquirt clone with a different processor - you use TunerStudio same as MS. That’s why I’ve still got an MS1 and haven’t bought a Speeduino yet..
|
|
|
|
|
|
|
right ok! just looking about and is there a problem using spi inlet on a mini with the turbo? they arnt dear, look easy to mod, and apparently they are the same thing as a Renault and many other cars. i don't know if there is a renault ecu that can work? but the guy i know with the rolling road specialises in renaults. Willg o and ask him
i take it mpi will be tooo much hastle to get working?
|
|
Last Edit: Nov 2, 2019 22:24:46 GMT by bmw2101
|
|
|
|
|
had a chat with teh RR guy, defo not injection, defo not speeduino if i want him to tune it which i can understand totally.
So ill be looking for either a megajolt or a new microsquirt.
just negotiating the price over a metro turbo plenum and intake manifold.
apparently "gas pipe" is what to use for the exhaust manifold, i don't know what my mate means exactly by this but he did a conversion on his e30 so will follow his advice...
thanks for all the advice here, and if anyone has a second hand megajolt??!
|
|
|
|
ChasR
RR Helper
motivation
Posts: 10,188
Club RR Member Number: 170
|
a+ 998 turboChasR
@chasr
Club Retro Rides Member 170
|
|
If Nodiz can work on a Turbo application, I'd also consider that. The price is around the same and you don't need to source an EDIS module either.
|
|
|
|